Re: [PATCH 03/13] xen: fix evtchn_unbind_from_user

[David Vrabel <david.vrabel@citrix.com>]

On 31/01/13 14:46, Wei Liu wrote:
> It is possible the port was allocated but the irq was not. Take care of this
> case.

I think the port should be closed when the evtchn_bind_to_user() fails
otherwise the evtchn driver is leaving the event channel in an
inconsistent state.

David

> Signed-off-by: Wei Liu <wei.liu2@citrix.com>
> ---
>  drivers/xen/evtchn.c |   12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/xen/evtchn.c b/drivers/xen/evtchn.c
> index b1f60a0..d2bbea1 100644
> --- a/drivers/xen/evtchn.c
> +++ b/drivers/xen/evtchn.c
> @@ -277,7 +277,17 @@ static void evtchn_unbind_from_user(struct per_user_data *u, int port)
>  {
>  	int irq = irq_from_evtchn(port);
>  
> -	unbind_from_irqhandler(irq, (void *)(unsigned long)port);
> +	/* It is possible that the port was allocated but the irq was
> +	 * not */
> +	if (irq >= 0) {
> +		unbind_from_irqhandler(irq, (void *)(unsigned long)port);
> +	} else {
> +		struct evtchn_close close;
> +		close.port = port;
> +		if (port != 0 && /* port 0 is never used */
> +		    HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
> +			BUG();
> +	}
>  
>  	set_port_user(port, NULL);
>  }